1. Field of the Invention
The present invention relates, in general, to vessel harvesting and, in particular, to a new and useful illuminated retractor for creating a working space for dissecting instruments in support of a surgical procedure such as a coronary bypass procedure or other type of vessel harvest procedures.
2. Background Art
In certain surgical procedures, it is necessary to remove a section of a blood vessel from a patient for use in another part of the patient's body or for transplanting into a second patient's body. For example, a section of the saphenous vein may be removed for use in coronary bypass surgery to replace coronary arteries which supply blood to the heart. As a result of aging and disease, coronary arteries may become blocked by plaque deposits, stenosis, or cholesterol. In some instances, these blockages can be treated with angioplasty, atherectomy or stent placement, and coronary bypass surgery is not required. Coronary bypass surgery is required when these other methods of treatment cannot be used or have failed to clear the blocked artery.
In the coronary bypass surgery, a vein is harvested from elsewhere in the body and grafted into place between the aorta and the coronary artery beyond the point of blockage. It is preferred to use a vein taken from the patient undergoing the bypass surgery since the patient is a ready source of suitable veins that will not be rejected by the body after transplantation. The saphenous vein in the leg is typically the best substitute for small arteries such as the coronary arteries because the saphenous vein is typically 3 to 5 mm in diameter (about the same size as the coronary arteries) and it is thus the preferred vein for use in coronary bypass surgery. Also, the venous system of the legs is sufficiently redundant so that after removal of the saphenous vein, other veins that remain in the leg are adequate to provide adequate return blood flow. The cephalic vein in the arm is an alternative that is sometimes used.
The conventional, non-endoscopic, surgical procedure for the removal of the long saphenous vein as a graft in coronary and vascular surgery may require the surgeon to make one long incision from the groin to the knee or the ankle of the patient's leg to allow access to the saphenous vein. Alternatively, if the surgeon uses several long incisions, one or more small skin bridges are left along the line of the incisions. While handling of the vein should be kept to a minimum, the vein must be separated from the connective tissue, and that requires the application of some force. After exposing the vein, the surgeon grasps it with his fingers while stripping off the surrounding tissues with dissecting scissors or other scraping instruments. The surgeon uses his fingers and/or blunt dissection tools to separate the vein from the surrounding tissue. To reach under the small skin bridges, the surgeon lifts the skin with retractors and dissects the vein free. When the vein has been completely separated from the surrounding tissue and the tributary veins that feed into the saphenous vein, the surgeon cuts the proximal and distal ends of the vein and removes the vein from the leg. After removal, the vein is prepared for implantation into the graft site and the long incisions made in the leg are closed, for example by suturing or staples.
As can be seen from the description of the conventional, non-endoscopic, vessel harvesting operation, the vessel harvesting operation is very traumatic in its own right. In the case of coronary artery bypass, this operation is carried out immediately before the open chest operation required to graft the harvested vein into the coronary arteries. Unfortunately, the vein harvesting operation is often the most troublesome part of the operation for the patent. The long incision, or incisions, involves the risk of injury to the medial lymph bundle and the risk of infection of the extensive operation site itself. The leg may thus, in addition to being very painful, be slow to heal, or may not heal properly, especially with those patients who have poor circulation in their extremities, and can consequently hinder the patient's recover from the operation. It is therefore desirable to perform the vessel harvesting procedure in as minimally invasive a manner as feasible.
One alternative for minimally invasive vessel harvesting uses an endoscopically controlled vessel removal. In contrast to the open long incision method, the surgeon can limit himself to 2-3 small incisions on the proximal thigh, at the level of the knee joint and perhaps the inner malleolus. Such minimally invasive or endoscopic vessel harvesting is known in the surgical field. Viewing the tools through an endoscope or laparoscope, or a video display from the endoscope, the surgeon typically grasps and holds the saphenous vein with a grasper which is introduced through the lumen of an endoscope. After connective tissue is dissected from around the vein, the vein is ligated and transected and removed via the lumen of the endoscope. Alternatively, as the vein is withdrawn into the lumen of the endoscope, the endoscope may be maneuvered along the length of the vein while side branches of the vein are ligated and transected whenever encountered. The endoscopic removal methods leave tissues intact and the vein is prepared and removed under visual conditions. With the same operating time relative to the vein harvesting, postoperative complaints and the risk of wound infection are considerably less than with the conventional, non-endoscopic, procedure.
There are several drawbacks to the endoscopic vessel harvesting method described above. First, the endoscopic or laproscopic methods require the surgeon to view the tools and the operating field through the distorted visual perspective provided by the endoscope, laparoscope, or the video display from the endoscope, which is a poor substitute for the actually visualization of the surgical field by the surgeon's naked eye. Second, compounding the first drawback, in practicing this method there is limited visibility of the saphenous vein and its side branches because viewing is limited to the immediate area directly in front of the endoscope. Third, the illumination within the subcutaneous space created by this type of endoscope is also limited to the light emitted directly at the distal portion of the endoscope. Another drawback to this type of procedure is that the side branches of the saphenous vein limit the maneuverability of the endoscope since the outer edge of the endoscope body is prevented from advancing along the trunk of the saphenous vein until the encountered side branches are ligated and transected thereby. Once freed, the endoscope is then maneuvered until the next side branch is encountered. Moreover, it has been found that methods that utilize this type of endoscope, i.e. an endoscope having a lumen, provide a working space that is very restricted because the side walls of the scope body constrain the working instrumentation to a limited area. It would be desirable to use a procedure that overcomes the drawbacks inherent to the endoscopic vessel harvesting method.
In an alternative minimally invasive technique for harvesting a blood vessel that overcomes the drawbacks of the endoscopic method, the surgeon utilizes 2-3 small incisions on the proximal thigh, at the level of the knee joint and perhaps the inner malleolus, which results in several long skin bridges between the incisions. To reach under the skin bridges, the surgeon lifts the skin with retractors and exposes the vein. After exposing the vein, the surgeon uses his fingers and/or blunt dissection tools to separate the vein from the surrounding tissues. It is desirable for the retractor to have some means of aiding the dissection of the surrounding tissues so that the trauma and time required for the procedure is limited. When the vein has been completely separated from the surrounding tissue and the tributary veins that feed into the saphenous vein, the surgeon cuts the proximal and distal ends of the vein and removes the vein from the leg. After removal, the vein is prepared for implantation into the graft site, and the 2-3 small incisions made in the leg are sutured or stapled closed. Because the dissection of the vein is accomplished by the surgeon's fingers and/or by blunt dissection, this technique may be accomplished by the surgeon in a more timely manner than the endoscopic method. This alternative technique is a minimally invasive technique that, just like the endoscopic method described above, consequently minimizes the risks and complications of the surgery.
This technique overcomes the endoscopic method drawbacks of limited movement and limited workspace of the procedure enabling instrumentation and the limited and distorted visual perspective provided by the endoscope, laparoscope, or the video display from the endoscope. However, one drawback remains. Using prior art retractors, the illumination of the surgical field is poor. By necessity of the minimally invasive nature of the procedure, the vessel harvesting procedure is primarily conducted under the long skin bridges left between the small incisions. Because the skin bridges are so long, it is difficult to sufficiently illuminate the subcutaneous space between the vessel and the subcutaneous tissue when retractors known in the art are used to retract the tissue away from the superior surface of the vessel. With insufficient illumination of the surgical field, the advantages of the surgeon being able to maneuver freely and to optically visualize the surgical field using the benefit of his own binocular vision during the course of the minimally invasive procedure are eroded. It is therefore desirable to provide a means of providing illumination to the subcutaneous space formed by the retractor so that the surgeon can efficiently view and operate in the entire surgical field exposed by the retractor.